#!/usr/bin/perl -wT
#
# Copyright (c) 2005 University of Utah and the Flux Group.
# 
# {{{EMULAB-LICENSE
# 
# This file is part of the Emulab network testbed software.
# 
# This file is free software: you can redistribute it and/or modify it
# under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or (at
# your option) any later version.
# 
# This file is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public
# License for more details.
# 
# You should have received a copy of the GNU Affero General Public License
# along with this file.  If not, see <http://www.gnu.org/licenses/>.
# 
# }}}
#

use English;
use Getopt::Std;

#
# Control tracing/monitoring on links.
#
sub usage()
{
    print(STDERR
	  "Usage: linkmon_ctl [-d] [-s vnode] <pid> <eid> <link> <action>\n".
	  "  pid = Project ID\n".
	  "  eid = Experiment ID\n".
	  " link = link name from ns file, ie. 'link1' in\n".
	  "        'set link1 [\$ns duplex-link \$A \$B 10Kb 0ms DropTail]'\n".
	  "action= One of pause, restart, kill\n".
	  "Options:\n".
	  "   -d = turn on debugging\n".
	  "   -s = Select the source of the link to determine which pipe\n");
    # Web interface cares about this return value!
    exit(2);
}
my  $optlist = "ds:";

#
# Configure variables
#
my $TB		= "@prefix@";
my $TBOPS       = "@TBOPSEMAIL@";
my $TEVC        = "$TB/bin/tevc";
my $debug	= 0;

#
# Testbed Support libraries
#
use lib "@prefix@/lib";
use libdb;
use libtestbed;

#
# Turn off line buffering on output
#
$| = 1;

#
# Untaint the path
# 
$ENV{'PATH'} = "/bin:/sbin:/usr/bin:/usr/sbin";
delete @ENV{'IFS', 'CDPATH', 'ENV', 'BASH_ENV'};

#
# Parse command arguments. Once we return from getopts, all that should be
# left are the required arguments.
#
%options = ();
if (! getopts($optlist, \%options)) {
    usage();
}
if (defined($options{"d"})) {
    $debug = 1;
}
if (@ARGV != 4) {
    usage();
}
# Locals
my $pid    = shift(@ARGV);
my $eid    = shift(@ARGV);
my $link   = shift(@ARGV);
my $action = shift(@ARGV);
my $srcvnode;

if (defined($options{"s"})) {
    $srcvnode = $options{"s"};

    if ($srcvnode =~ /^([-\w]+)$/) {
	$srcvnode = $1;
    }
    else {
	die("*** Bad srcvnode name: $srcvnode.\n");
    }
}
#
# Untaint args.
#
if ($pid =~ /^([-\w]+)$/) {
    $pid = $1;
}
else {
    die("*** Bad data in pid: $pid.\n");
}
if ($eid =~ /^([-\w]+)$/) {
    $eid = $1;
}
else {
    die("*** Bad data in eid: $eid.\n");
}
if ($link =~ /^([-\w]+)$/) {
    $link = $1;
}
else {
    die("*** Bad data in link: $link.\n");
}
if ($action =~ /^([\w]+)$/) {
    $action = $1;
}
else {
    die("*** Bad data in action: $action\n");
}
usage()
    if ($action ne "pause" &&
	$action ne "restart" &&
	$action ne "kill" &&
	$action ne "snapshot");

# Permission check.
#
if ($UID && !TBAdmin($UID) &&
    ! TBExptAccessCheck($UID, $pid, $eid, TB_EXPT_MODIFY)) {
    die("*** $0:\n".
	"    You do not have permission to modify the delay parameters!\n");
}

#
# No transitional experiments.
#
my $estate = ExpState($pid, $eid);
if (! $estate) {
    die("*** $0:\n".
	"    No such experiment $pid/$eid exists!\n");
}
if ($estate ne EXPTSTATE_ACTIVE) {
    die("*** $0:\n".
	"    Experiment $pid/$eid must be ACTIVE\n".
	"    to control its tracing/monitoring\n");
}

#
# Link or Lan!
# 
$query_result =
    DBQueryFatal("select member from virt_lans ".
		 "where pid='$pid' and eid='$eid' and vname='$link'");
if (!$query_result->numrows) {
    die("*** $0:\n".
	"    $link is not a link in $pid/$eid!\n");
}
my $islink = ($query_result->numrows == 2 ? 1 : 0);

#
# Inject an event. 
#
my $inject_string = "$TEVC -e $pid/$eid now $link";

# Direct the event to the whoever is handling this particular delay.
$inject_string .= "-${srcvnode}"
    if (defined($srcvnode));

# XXX The actual agent name. Yuck!
$inject_string .= "-tracemon";

#
# Map action
#
if ($action eq "pause") {
    $action = "STOP";
}
elsif ($action eq "restart") {
    $action = "START";
}
elsif ($action eq "stop") {
    $action = "KILL";
}
elsif ($action eq "snapshot") {
    $action = "SNAPSHOT";
}
$inject_string .= " $action";

if ($debug) {
    print "$inject_string\n";
}

system($inject_string) &&
    die("*** $0:\n".
	"    Failed to inject delay update event!\n");
    
exit(0);